Want to keep your workers safe around medium-voltage equipment?
Medium-Voltage Switchgear risk assessments can kill you when it malfunctions. There’s enough energy released during an arc flash in a 15kV cabinet to match a stick of dynamite detonating 1 foot away from your face.
The good news?
Implementation of a thorough risk assessment process can prevent most of these occurrences from ever occurring. Furthermore, most arc flash incidents can be completely eliminated by following the correct safety procedures.
Why switchgear risk assessments matter so much?
Medium-voltage switchgear safety is not optional. OSHA 1910.269 and NFPA 70E make it mandatory. Medium-Voltage Switchgear risk assessments, however, are priceless.
The statistics are eye-opening.
NFPA reports around 400 deaths happen yearly across the US from arc flash incidents. Additionally, arc flashes cause 7k burn injuries and 2k hospitalizations. Electrical injuries are also rapidly increasing. The Electrical Safety Foundation reported 5,180 electrical injuries occurred in 2023-2024. This is a 59% increase from the prior two-year period.
That is why it is crucial to work with a reputable medium-voltage switchgear manufacturer. High-quality medium-voltage switchgear and a thorough risk assessment provide your team the highest opportunity to prevent a serious injury. Well-designed equipment, proper arc flash labels, and thoroughly documented safety procedures all begin with your choice of manufacturer.
Pretty important, right?
Let’s break down how to do it properly…
The core steps of a switchgear risk assessment
Performing a Medium-Voltage Switchgear risk assessments is not intuitive. There is a method to the madness. While NFPA 70E provides a general outline, here is what every risk assessment should include:
- Identify the hazards: Arc flash, shock, blast pressure, toxic gas release
- Calculate incident energy: Determine worker exposure using IEEE 1584-2018 equations
- Set approach boundaries: Know exactly how close anyone can safely get
- Pick the right PPE: Match the gear to the calculated incident energy
- Document everything: Labels on equipment, written procedures, training records
The one thing most facilities fail to understand … A risk assessment is NOT a set it and forget it type of thing. It must be revisited every 5 years at LEAST, or when equipment changes.
That’s where things go wrong for a lot of operations.
Best practices that actually work
Now to the good stuff.
The difference between safe facilities and those featured in OSHA news releases lies in these best practices. Select a few that you can implement this week.
1. Start with an up-to-date single LINE diagram
You can’t assess what you can’t see.
The first step in every risk assessment is to have a detailed single-line diagram of your entire electrical system. You should have this available that depicts:
- All sources of power (utility plus generators)
- Every transformer, breaker, and switchgear lineup
- Protective device settings
- Cable lengths and types
If your single-line diagram isn’t updated, everything else in your evaluation is incorrect. Incorrect evaluations lead to incorrect PPE choice…which results in catastrophic injuries.
2. Use qualified personnel only
NFPA 70E is crystal clear on this one.
Only “qualified persons” are allowed to do energized electrical work on Medium-Voltage Switchgear risk assessments. Qualification is specific to each piece of equipment. Just because you are qualified on 480V panels does not make you qualified on 15kV switchgear.
Make sure your qualified workers have:
- Documented training on the specific equipment
- Knowledge of the hazards involved
- The ability to recognize unsafe conditions
- Proper test equipment skills
Don’t cut corners here. The risk is way too high.
3. Spec arc-resistant switchgear where possible
Arc-resistant switchgear represents one of the highest forms of engineering controls available today. By design, arc flash energy is directed away from workers through built-in exhaust vents and reinforced enclosures.
When buying new equipment from a Medium-Voltage Switchgear, ask about:
- IEEE C37.20.7 certification
- Internal arc classification ratings
- Ducted exhaust systems
- Pressure relief design
It costs more upfront. But the safety payoff is massive.
4. Reduce incident energy at the source
This is where things get interesting…
Legacy switchgear often has incident energy ratings greater than 40 cal/cm². Greater than NFPA 70E PPE Category 4. There is no commercial PPE to provide total worker protection at those levels.
The fix? Reduce the incident energy at the source. You can do this with:
- Arc flash detection relays: Trip faster than traditional relays (2-4 ms vs 50-100 ms)
- Maintenance mode switches: Temporarily reduce trip times during energized work
- Zone selective interlocking: Smarter coordination between protective devices
- Optical arc sensors: sense arc light and trip breaker before arc fully develops
Upgrade combinations can reduce incident energy by 80% or more. That difference can mean a Category 4 incident vs. Category 1.
5. Label every piece of equipment clearly
OSHA and NFPA 70E both mandate arc flash labels on Medium-Voltage Switchgear risk assessments. Required content for each label includes:
- Nominal system voltage
- Arc flash boundary distance
- Incident energy at working distance
- Required PPE category
- Date of the most recent study
No labels, Faded labels, Old labels = Out of Compliance. Replace them today.
Common mistakes to avoid
Here are the biggest medium-voltage switchgear safety mistakes seen in the field:
- Skipping the short-circuit study: You need this data to do any meaningful assessment
- Ignoring protective device coordination: Wrong settings mean wrong incident energy calculations
- Using generic PPE: Different tasks need different PPE levels
- Letting assessments go stale: Equipment changes invalidate old studies
- Skipping refresher training: Workers forget. That’s normal. Train them again
Correct these few issues, and your safety program will be light-years ahead of most facilities.
Final thoughts
Medium-voltage switchgear risk assessments should never be a checkbox item. They’re the backbone of any safe electrical program. With the proper risk assessment process in place, you can protect:
- Workers from career-ending injuries (and worse)
- Equipment from preventable damage
- Operations from costly downtime
- Your business from regulatory fines and lawsuits
To quickly recap:
- Start with an accurate single-line diagram
- Only use qualified personnel on energized work
- Spec arc-resistant gear from a quality manufacturer
- Reduce incident energy with modern protection
- Keep your arc flash labels current
- Avoid the common pitfalls
Follow these, and you’ll have a medium voltage switchgear safety program that will pass muster with OSHA. With your insurance carrier. But most importantly, with your own employees who rely on it daily.
Safety is never a one-time thing. Keep up with it, follow the best practices listed above, and the numbers will take care of themselves.
